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How to estimate alfalfa quality in the field using PEAQ

How to estimate alfalfa quality in the field using PEAQ

Here, you’ll find guidance on how to determine alfalfa relative feed value (RFV) and neutral detergent fiber (NDF) levels.

You can estimate both with the Predictive Equations for Alfalfa Quality (PEAQ) system, which gives alfalfa producers a simple way to schedule harvests. A PEAQ stick can be a useful tool when implementing this approach.

How to estimate alfalfa relative feed value (RFV)

  1. Choose a representative 2-square-foot area in the field.
  2. Determine the most mature stem in the 2-square-foot sampling area using the criteria shown in Table 1.
  3. Measure the length of the tallest stem in the 2-square-foot area. Measure it from the soil surface (next to plant crown) to the tip of the stem (not to the tip of the highest leaf blade). Straighten the stem to accurately measure its length. The tallest stem may not be the most mature stem.
  4. Based on the most mature stem and length of the tallest stem, use Table 1 to determine the standing alfalfa forage’s estimated RFV content.
  5. Repeat steps 1 to 4 in four or five representative areas across the field. For fields larger than 30 acres, sample more times.
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How to estimate alfalfa neutral detergent fiber (NDF)

This approach uses PEAQ with a simplified staging scale:

  1. Choose a representative 2-square-foot area in the field. This will be the sampling area.
  2. Determine the most mature stem in the sampling area using the criteria shown in the table.
  3. Measure the length of the tallest stem in the sampling area. Measure it from the soil surface (next to plant crown) to the stem’s tip (not to the tip of the highest leaf blade). Straighten the stem to accurately measure its length. The tallest stem may not be the most mature stem.
  4. Based on the most mature stem and length of the tallest stem, use the table to determine estimated NDF content of the standing alfalfa forage.
  5. Repeat steps 1 to 4 in four or five representative areas across the field. For fields larger than 30 acres, sample more times.
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Reviewed in 2018

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